This invention relates to an improved mosquito coil composition and process for making this improved mosquito coil. More particularly, this invention relates to an improved mosquito coil composition utilizing potato starch as a binder for the mosquito coil.
The manufacture of mosquito coils is an art which has been practiced for a number of years. Mosquito coils comprise a material which burns emitting smoke combined with an insecticide. Mosquito coils are often used to knock down or repel flying insects in living quarters.
Traditional mosquito coil compositions include approximately 25% or more of a residue from preparing pyrethrum known as pyrethrum marc, as it is thought this material is a necessary ingredient to produce an acceptable mosquito coil. In addition to the pyrethrum marc, the prime burning agent or fuel used for mosquito coils is coconut shell flour, tabu powder, sawdust, ground leaves, ground bark, starch, etc.
Representative patents describing mosquito coils are U.S. Pat. Nos. 3,248,287, 3,723,615 and 3,819,823. The latter two patents are primarily directed to insecticides for use in mosquito coils and describe the use of various mosquito coil carrier ingredients such as wood powder and starch.
It has unexpectedly been found that a high quality mosquito coil composition can be prepared by utilizing from16- 25% by weight based on dry ingredients of potato starch as the binder for the traditional mosquito coil carrier material. It has also been found that these improved mosquito coils may be prepared by a method which involves dispersing the potato starch in water which has a temperature just below the gellation point of the potato starch, adding sufficient hot water to this water-starch mixture to raise the temperature above the gellation point of the potato starch, adding the dry ingredients to the mosquito coil, extruding the coil into a ribbon, stamping the mosquito coils from this ribbon, and allowing these coils to dry.
The coils prepared using the composition of the present invention and the method of the present invention have good burning properties lasting up to 7 or 8 hours and have better structural integrity than coils made using other starches.
It is, therefore, the primary object of the present invention to prepare a mosquito coil composition utilizing potato starch as a binding agent.
It is a further object of the present invention to provide a mosquito coil composition having improved burning properties and structural integrity.
It is a still further object of the present invention to provide a mosquito coil composition having controllable and even-burning properties.
It is a still further object ofthe present invention to provide a process for quickly and easily producing high quality mosquito coils.
Other objects and advantages of the mosquito coil composition and process for preparing the same will become more apparent from the following, more detailed description thereof.
The mosquito coil compositions of the present invention comprise on a dry weight basis from 16- 26% by weight of potato starch, from 72- 83% by weight of a mosquito coil carrier agent, from 0- 2% of a burning aid, from 0.5- 3% by weight of an insecticidal material.
The method of the present invention comprises dispersing potato starch in water heated to a temperature of 30- 65.degree. C., gelling the starch by adding sufficient water having a temperature of from 80- 95.degree. F. to the starch-water dispersion to raise the temperature of the mixture to above the gelling point of the starch, adding the mosquito coil carrier to the gelled starch-water mixture, forming the composition into a thin sheet, forming the mosquito coils from this thin sheet and drying the formed mosquito coils.